Automated measurement of human basophil degranulation.

Basophils disappear after challenge with specific antigen. A human basophil degranulation test has been carried out on a slide using an enriched cell suspension. On each slide, the same volume of cell suspension was deposited in wells with antigen diluted in buffer or with buffer only (control). The basophil count was made on an equal number of randomly distributed microscopic fields either by eye (optical) or by image analyser (automatic). In 33 subjects, the correlation coefficient between the numbers of non-degranulated basophils counted by eye and by image-analyser on control wells was found to be r-0.91, p less than 10-8. In 12 patients (6 with hydatidosis and 6 with schistosomiasis), the percentage of degranulation with three antigen dilutions was measured. The correlation between the results obtained by eye and by image-analyser reached 0.76 (p less than 10-7). The authors now use the automated measurement of human basophil degranulation routinely.